Appliance knob



FIG. 1 is a front perspective view of the design of the appliance knob;

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevational view with the left side being a mirror image thereof; and,

FIG. 4 is a front elevational view thereof.

The broken lines shown are for illustrative purposes only and form no part of the design claimed. 

The ornamental design for an appliance knob, as shown and described. 